The present invention relates to paired light shielding flange members which are fitted into both ends of a hollow cylindrical core on which a rolled type photosensitive material has been wound.
Hitherto, rolled type photosensitive materials have been packed to conform to so-called ambient light loadable packages. Ambient light loadable packages are structured in such way that, a wide and long photosensitive material is rolled up on a hollow cylindrical core, and light shielding flange members are fitted into both ends of the core, after a light shielding leader, which is wider than the rolled-up photosensitive material, is adhered to the end of the rolled-up photosensitive material, after which the light shielding leader is wound up onto the rolled-up photosensitive material, so that the peripheral sections of the light shielding flange members, fitted into both ends of the core, are covered by the light shielding leader, resulting in light shielded packaged photosensitive material which is capable of being loaded into a magazine of a photographing apparatus in ambient light.
When the rolled type photosensitive material packaged to conform to ambient light loadable package (hereinafter referred to simply as ambient light loadable package), is employed, the end of the light shielding leader is pulled slightly, next the ambient light loadable package is loaded into an exclusive magazine of a photographing apparatus in ambient light, then the magazine is loaded into the photographing apparatus for use. Accordingly, light shielding is very important for ambient light loadable packaged photosensitive material.
For this purpose, when the light shielding leader is wrapped on the rolled-up photosensitive material to make the light shielded package, in order to prevent light from entering the edges of the photosensitive material, the light shielding flange members are fitted to both end sections of the rolled type photosensitive material.
The thickness of the employed light shielding flange member depends upon the type of magazines to be loaded into the photographing apparatus, being classified into two types, a thin type of 0.3 to 1.0 mm, and a thick type of 2.0 to 4.0 mm. Of the light shielding flange members, the thick type can be produced by a normal injection molding (refer to the handbook of plastic processing technology, pages 427-647, Society of Polymer Science, Japan). The thin type can be produced by a normal vacuum molding, pneumatic molding (refer to the handbook of plastic processing technology, pages 945-959, Society of Polymer Science, Japan), and injection molding (refer to the handbook of plastic processing technology, pages 427-647, Society of Polymer Science, Japan).
After being loaded into the magazine, the magazine is loaded into the photographing apparatus. There are two cases of usage of the photosensitive material in the magazine. One is that all of the photosensitive material in the magazine is completely used up, and the other is that the use of the photosensitive material in the magazine is discontinued halfway and is changed to another type of photosensitive material. For the latter case, the magazine is firstly unloaded from the photographing apparatus, a light shielding leader, which is wider than the photosensitive material, is spliced onto the end of the photosensitive material which slightly appears from the magazine, after which the photosensitive material in the magazine is rewound, and thereby, the light shielding leader is forced to back into the magazine, and is wound around the photosensitive material, and also around the circumferential sections of the flange members fitted into ends of the core, resulting in a light shielded package. Finally, the light shielded package of the photosensitive material is pulled out from the magazine and is stored for the next use.
Due to usage of ambient light loadable packaged photosensitive material as described before, the user requires that the light shielding flanges used therein meet the following functions.
(1) In order to perform complete light shielding, when a hollow cylindrical boss section of the light shielding flange section is inserted into the core, the hollow cylindrical boss section must fit firmly into the hollow cylindrical section of the core.
(2) In order to stably supply or rewind the photosensitive material from or into the magazine, an inner surfaces of the hollow cylindrical boss sections of the light shielding flange members must be fixed to an inner shaft of the magazine without play or back-lash, and still further, must be easily fixed or detached.
(3) In the case when the photosensitive material in the magazine is discontinued halfway and another type of photosensitive material is employed, a light shielding leader which is wider than the photosensitive material is spliced onto the end of the photosensitive material which slightly appears from the magazine, after which the photosensitive material in the magazine is rewound, and thereby, the light shielding leader is forced to enter the magazine, and is wound around the photosensitive material, and also around the circumference of the flange members fitted into the core, and the light shielded package is made again in the magazine and when the light shielded package is taken from the magazine, that is, when the hollow cylindrical boss section of the flange member having the photosensitive material is pulled from the inner shaft of the magazine, the light shielding flange member must not be separated from the core.
Concerning the functions required of the light shielding flange member, the following characteristics apply to both the thicker and the thinner type light shielding flange members.
In the case of the thicker type light shielding flange member, concerning the functions shown in (1) to (3), injection molding method can be employed for its production, and in particular, for (1), ribs are formed on the periphery surface of the hollow cylindrical boss section.
In the case of the thinner type light shielding flange member, concerning the function shown in (1), it is processed in such a way that a vinyl tape is wound on the outer periphery surface of the hollow cylindrical boss section. However, for recycling after use, the vinyl tape must be removed, and further, it is troublesome to wind the tape onto the outer periphery surface of the hollow cylindrical boss section, which are drawbacks. Concerning the functions shown in (2) and (3), they are processed in such a way that the light shielding flange member is made by a vacuum molding or a pneumatic molding method having higher dimensional accuracy, but at lower productivity and higher cost, which are also drawbacks.
As countermeasures to the drawbacks of the thin type light shielding flange member, described above, a thin typed light shielding flange member made by the injection molding method is disclosed in TOKKAIHEI 8-62783 which has a 0.3-1.0 mm flange, and ribs are provided on the outer circumferential surface of the hollow cylindrical boss section of the light shielding flange member, in order to make firm contact between the hollow inner cylindrical section of the core and hollow cylindrical boss section of the light shielding flange member. However, though production cost by the injection molding method is more favorable than production cost by the vacuum molding or pneumatic molding method, the thin type light shielding flange member disclosed in TOKKAIHEI 8-62783 is not sufficient to counter the above-described functions (1)-(3) which are required of the light shielding flange member, because of the following reasons.
(1) Since the thickness of the section where the rib is provided on the hollow cylindrical boss section is different from the thickness where there is no rib, a change of thickness results during the injection molding process, and thereby the thickness of the hollow cylindrical boss section is not uniform, and further, the form of the produced hollow cylindrical boss sections is also not uniform. When such light shielding flange member is inserted into the hollow cylindrical section of the core of the rolled type photosensitive material, the connection between the hollow cylindrical boss section and the core is not secure, and thereby they may become separated, during the production of the ambient light loadable package.
(2) Since the thickness of a section where a rib is provided on the hollow cylindrical boss section is different from the thickness of a section where there is no rib, when the inner shaft of the magazine is inserted into a hollow section of the light shielding flange member, the hollow cylindrical boss section rarely expands uniformly, resulting in abnormal setting of the ambient light loadable package into the magazine.
(3) When the inner shaft of the magazine has been firmly inserted into the hollow cylindrical boss section of the light shielding flange member, the following situation may happen. That is, when the photosensitive material in the magazine is changed at the halfway point to another type of photosensitive material, a light shielding leader which is wider than the photosensitive material, is spliced onto the end of the photosensitive material which slightly appears from the magazine, after which the photosensitive material in the magazine is rewound, and thereby, the light shielding leader is forced to enter the magazine, and is wound around the photosensitive material, and also around the circumferential sections of the flange members fitted into both ends of the core, resulting in a light shielded package, and finally when the light shielded package of the photosensitive material is removed from the magazine, that is, when the inner shaft of the magazine is removed from the hollow cylindrical boss section of the light shielding flange member, the light shielding flange member is also removed from the core, resulting in undesirable exposure of the photosensitive material.
(4) When an unstable supply of resin occurs during injection molding, it is very difficult to obtain uniform flatness of flange section.
If such a flange is used for packaging of the photosensitive material, the light may enter either or both side surfaces of the rolled photosensitive material, resulting in an ineffective light shield.
Under the conditions mentioned above, expected is development of a light shielding flange member, wherein the hollow cylindrical boss section of the light shielding flange member is fixed in the hollow cylindrical inner section of the core without using supplementary parts, the inner shaft of the magazine is fixed without loosening and is easily removed from the inner wall of hollow section of the hollow cylindrical boss section of the light shielding flange member, the production cost is inexpensive, and the production can be stably achieved.